Train control



July 20 1926.

W. K. HOWE TRAIN CONTROL Filed July 11, 1924 Iii) Patented July 20, 1926.

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WINTHROP K. HOWE, OF ROCHESTER, NEW YORK, A SSIGNOR TO GENERAL SIGNAL COMPANY, OF ROCHESTER, NEW YORK.

RAILWAY TRAIN CONTROL.

This invention relates to an automatic train control system of the type now known as the continuous inductive train control system.

It is desirable in certain railway systems to employ train control means which operate to bring a moving train or vehicle substantially to a stop whenever a caution or danger signal is passed. It is also desirable to employ a system in which control in fluences are continuously transmitted inductively to the moving vehicle in order that danger frombroken rails, a train backing into the same block or entering that block from a siding, may act to restrict the speed of a following train.

It is one object of this invention to provide a simple and efficient automatic stop system, operating on the continuous inductive principle, which will act to bring the train substantially to av stop when a danger or caution signal is passed or when other dangerous traflic conditions arise.

t is another object of this invention to provide means for the operation of trains equipped for automatic train control of the type described, over sections of trackway unequipped fortrain control operation.

Further objects, advantages and desirable features of the invention will be apparent or pointed out as the description ofits construction and-operation progresses.

Referring. to the drawings, there has been shown a diagrammatic representation of a section of track rails equipped for automatic train rontrol of the type. embodying this invention, together with the car-carried apparatus and circuits for use therewith.

Referring more particularly to the track rails and their associated circuits, the rails 1 and 2 are dividedinto blocks by the insulated joints 3, the blocks I and the adjacent ends of two other blocks H and J having been shown. It is to be understood that the constructionand operation of the apparatus used in the several blocks is identical, and for this reason a detailed description of one from the battery terminal G, through the block only will be given, corresponding elements in the several blocks being referred to by like reference characters having distinctive exponents.

Alternating current track relays 4, of the type commonly used in signaling practice, are locatedat the entrance ends of the block, the normal direction of trailic being from Application filed July 11,

1924. Serial No. 725,395.

left to right, as indicated by the arrow. These contacts, and all other contacts and devices in the drawings, are shown in their normalposition, i. e., the positions that would be taken under clear traflic conditions ahead.

lVayside signals of the semaphore, light signal, or other well known type are pref erably used in connection with these track relays. For the purpose of illustration semaphore signals Z have been convention ally represented at the entrance end of each block. These wayside signals are operated from the track relays 4, but since the signal operating means used forms no part of this invention, and since such means are .now common in railway signaling practice, the control circuits between the track relays and the semaphore signal have not been shown.

The track relays 4 are maintained energized through a track circuit which may be traced as follows beginning at the secondary of transformer 7, wire 8, front contact of finger 9 of linerelay SR, wire 10, track rail 1, wire 11., the winding of track relay 4, wire 12, track rail 2, wire 13, front contact of finger 14 of relay SR, wire 15 to the secondary of transformer 7. The primary winding of the transformer 7 is maintained energized from a transmission line 16 as shown, preferably of a commercial frequency, such as 60 cycles. It is obvious that if the line relay SR is deenergized, dropping its contact fingers 9 and 14, the track circuit and train control currents will be impressed on the track rails at the points 17 and 18 through the back contacts of said fingers, in. stead of at the points 19and 20. Thedistance between the two points of application of the control current to the rails is relatively short, but is slightly longer than the longest dead section distance as hereinafter explained.

The line relay SR is located at the exit end of each block, and is energized through a circuit which in the case of the relay SR for the block I, may be traced as follows 2- winding of relay SR wire 21, front contact (5 of track relay 4, wire 22, front contact 5 of track relay 4 to-the battery terminal B.

If a train is located in the block J, its wheels and axles will shunt the track relay 4 and cause it to drop its contact fingers 5 and 6 This Will cause the deenergization of the line relays SR and SR, dropping their contact fingers 9, 14, 9 and 14 and causing the point of application of the control current to be shifted from the point 1920 to the point 17-18 in the block I, and from the point 19"20 to the point 17 18 in block H, thus providing a dead or de-energized section of track at the exit end of each of these blocks. When the train passes out of block J, the track relay st and line relays SR and SR will be energized, and the application point of the control current to the rails will be shifted to points l920 and 192O in the blocks H and J respectively.

A railway vehicle has been conventionally illustrated in the block H by the wheels and axles 23. Mounted in front of the leading axle of this vehicle, above and in inductive relation to the track rails, is a pair of receiving coils 24 which may or may not have laminated iron cores.

opposite directions in the two track rails induce additive currents in these coils. The coils 24 are resonated at the frequency of the train control current by means of the condenser T, and are connected by wires 25 and 26 to an amplifier which has been conventionally represented at A. This amplifier may be of any suitable construction, preferably of the vacuum tube type. and serves to amplify the comparative weak currents induced in the receiving coils 2% so that sulficient energy may be provided for the operation of the car-carried control apparatus.

The amplifier output circuit is connected by the wires 27 and 28 to a main car relay MB. This relay may be of any suitable type and is preferably of the alternating current type, having its contacts biased, counterweighted or otherwise arranged to be retracted when this relay is de-energized.

The relay MR is provided with a movable contact finger 29 which, in its normal position, completes a stick circuit to a control relay CR which may be traced as follows from battery terminal B, through contact finger 29 of relay MR and its front contact, wire 30, front contact 31 of control relay CR, wires 32 and 33, winding of relay CR to battery terminal C.

In systems of the type embodying this invention, it is apparent that the control relay CR would normally be de-energized whenever the receiving coils 24 tail to pick up current from the track rails. In the practical application of this invention to existing railway systems, points are encountered, such as staggered joints, crossings, switch frogs, and the like, where it is difiicult to maintain the supply of current to the receiving coils 24:. In order that the control relay CR may not open its contacts when the main relay MB is de-energized by lack T hese'coils 24: are so connected in series that current-s flowing in of current at such dead sections, the control relay CR is made slow acting by some suitable means, :tor instance. its construction may include a copper sleeve around the core, causing the flux generated by a direct current in its windings to build up and cecrease slowly. The time required for the operation of the control relay GR is so arranged that the longest dead sections ordinarily encountered may be crossed without a de-ener gization of this relay if the train is traveling above a given speed.

The reset push button is preferably located in a box or housing, accessible only from the ground, in order that the train must be brought to a stop before this push button can be operated and the train released from the automatic brake application as hereinbefore described. If desired. the resetpush button RB may be equipped with a counter or recorder, so that the number o5. times that this push button is operated by the engineer may be known. This reset push button is provided with two contact fingers. 3i and 35. The contact finger 3 1 is nor- 'nially open, and when closed completes a circuittln-ough wire 36, energizing the control relay CR, as plainly shown in the drawings. The contact finger 35 is normally closed, and is included in the energizing circuit for the electro-pneumatic valve EPV.

which circuit may be traced as follows 7 from the battery terminal C, through the winding of the elcctro-pneuinatic valve EPV, wire 37, contact 35 of reset push button RB, wires 38 and 39, front contact 40 o F control relay CR, wire 4-1, contact finger 42 of non-control push button NB to the battery terminal B.

The electro-pneuniatic valve EPV may be of any suitable type and acts to apply the regular air-brakes of the train when the circuit to its coils is broken. This valve EPV may act directly on the engineers brake valve, or on a separate brake controlling unit, but is preferably so constructed and arranged that it may not be manually operated.

The non-control push button NB has two movable contact fingers 42 and 43. The contact 42 is normally closed and is included in a circuit for the electro-pneiunatic valve EPV which has been traced above. The contact finger 43 is normally open. and when closed completes a pick-up circuit for the non-control relay NC, which circuit obvious from the drawings.

The non-control relay NC has two contact lingers 4d and 45. A stick circuit for this non-control relay NC includes its contact linger 4A- and the Contact finger 2!) of the main relay MR, this circuit being traced as follows :from the battery terminal B through contact finger 29 of main relay MR, wire a6, contact finger 44 of non-control re- JlO valve is ener lay NC, -wires'47 and 48, winding of noncontrol relay- N C to the battery terminal C. The contact finger 45 of the non-control relay NC is normally open, and when closed, shunts the front contact of finger 29 of the main relay MR, and the contact finger 31 of control relay CR, supplying energy to the control relay CR and maintaining this control relay energized as long as the non-control relay NC is energized. With the control relay CR energized, the electro-pneumatic valve EPV is maintained energized through a circuit including the contact finger 40 of the control relay CR, which circuit has been traced above.

Operation: In the drawings, all contacts and devices have been shown in their normal positions,"i. e., assuming clear traflic conditions ahead and assuming that normal track circuit and train control currents are flowing in the track rails. Under these conditions, currents will be induced in the receiving coils 24 of the vehicle, these. cunrents being amplified by the amplifier A and energizing the main car relay MR.

Thismain car relay'MR maintains the control relay CR energized, which in turn maintains the electro-pneumatic valve EPV energized. When this electro-pneumatic gized, the train may proceed without restriction. 1

Now assume that as the train 23 proceeds in the blockH, another train is located in the block J. The presence of the train in block J will deenergize the track relay 4 causing it to drop its contact fingers 5 and 6 and change the application point of the train control current from the point 19-20 to the point 17-18 in block I, and from the point 19? 20 to l7--18 in block H, as explained above. When the following train 23 proceeds into the track section between thepoints1718 and 1920 in block I-I, its receiving coils 24 will no longer be energized. This will cause the main car relay MB to drop its contact finger 29, breaking the stick circuit to the control relay CR, opening its front contact 40 and so- (16-811;- ergizing the "electro-pneumatic valve EPV. This will cause an automatic brake application, which will be maintained until the control relay CR is reset. As the train proceeds into theblock I, the receiving coils 24; will again receive train control current from the rails, the mainrelay MR will be energized, but the control relay CR, being a stick relay, ,is not energized. The brakes remain applied until the train is brought to a stop, whereupon the engineer may dismount from the cab and operate the reset push .button RB. The operation of the reset push botton RB energizes the control relay CR through a circuit which is obvious from the drawings. Once re-energized, this control relay is stuck up through its stick circuit ineluding thefront contact of finger 29 of the main car relay MB. The re-energization of control relay CR reenergizes the electropneumatic valve EPV through a circuit which has been traced, thus permitting re} lease of the brakes and'allowing'the train to proceed unrestricted in block I. The train may now proceed unrestricted until it pneumatic valve when the reset push button is depressed. If the engineer should'fasten the reset push button down, in order to avoid automatic control, the electro-pneumatic valve is deenergized and the train could not proceed.

If, while the train is traveling in a block, a track rail should break, a switch should be opened, a train should enter the block from a siding, or any other dangerouscondition should arise, the supply of train control current is cut ofi from the rails in that block, the main-relay MB is deenergized and the stick circuit to the control relay CE is broken, causing the de-energization of this relay and the subsequent d'e-energization of the electro-pneumatic valve EPV, thus causing an automatic brake; application and bringing the train to a stop as described above. 7

When the train enters a section of track way not equipped for automatic train control, the non-control push button NB is depressed by the engineer. This non-control push button is preferably protected by being enclosed in a locked or sealed box, the key of which is in the possessionot' the conductor, or a tower man or other oflicial located at the point where the unequipped section of trackway begins. The box enclosing the non-control push button may also be equipped with a counteror recorder, which records the number of times that this push button is operated. This will serve as a check on the engineer and prevent his misuse ofthis push button to relieve the train from automatic control when traveling over a sec.- tion of trackway having train control equipment.

The depression of the non-control push button NB energizes the non-control relay NC through the contact finger 4:3 and a circuit which is obvious from the drawings. As the receiving coils 24 are no longer receiving train control current from the rails, the main car relay MB is de-energized, and its contact finger 29 is in the lower position. The non-control relay NC will now be stuck up through a stick circuit includ ing the back contact of finger 29 of main car relay MR, as clearly shown in the drawings. As the main relay MB is de-energized, the front contact of its finger 29 is opened and the stick circuit to the control relay CR is broken, causing the de-energization of this control relay. After the non-control relay NC has been energized, the control relay CR will be re-energized through a circuit including the contact finger d of the non-control relay NC and the wires 49, 32 and 33, which circuit is obvious from the drawings. Once re-energized, the control relay CR will be maintained energized as long as the non-control relay NC is energized. The eleetro-pneumatic valve EPV will now be maintained energized through a circuit including the contact finger 4.0 of the control relay CR, which circuit has been traced. It is evident from the above that the electro-pneumatic valve will be maintained energized as long as the train is traveling in uncquipped territory so that the train may proceed without restriction in such territory.

It should be noted that the non-control push button NB is also protected against abuse by the engineer. hen this push button is held down, the circuit to the electropneumatic valve through contact finger of the non-control relay NC can not be completed, for the reason that contact fin ger 42 of the non-control push button is open. For this reason the engineer may not hold or fasten non-control push button down to release the train from automatic control when traveling over an equipped section of traekway.

When the train again enters a section of traekway equipped for train control, the receiving coils 24 will again receive energy from the rails and the main car relay MR will be energized. The finger 29 of this relay will be lifted, breaking the circuit to the non-control relay NC and causing its contact fingers 44 and 45 to return to their deenergized positions. As the main relay MR is energized, its finger 29 closes its front contact, maintaining the control relay CR energized through the stick circuit of this relay. The electro-pneumatic valve EPV will be maintained energized through the contact finger 40 of the control relay CR, and the train may then proceed in the equipped territory under automatic stop control as described above.

In order that the control apparatus may be returned to its active conditions on the return of the train to territory equipped for train control operation regardless of trafiic conditions in the first equipped block encountered. a permanently energized section of trackway may be provided at the entrance end of such first equipped block.

This permanently energized section will always act to re-energize the main relay MR, (lo-energizing the non-control relay NC and so returning the car-carried apparatus to its active condition as described above.

It is seen from the above that an automatic stop system has been provided which will continuously protect a train against dangerous trafiic conditions ahead, and which will bring the train to a stop by automatic means at the entrance to a block in which danger or caution traflic conditions exist. It is also clear that means have been provided for operating a train equipped with this system over sections 01'? trackway which are not equipped for train control operation. Means have also been provided for resetting the automatic brake applying device after an automatic stop, so

that the train may proceed for at least one block after such stop has been efiected.

it should be clearly understood that the apparatus and circuits described in connection with this invention have been used to illustrate the nature of the invention only, and should not be considered as limiting its scope. The system described above is capable of many modifications, additions, adaptations and changes without departing from the spirit of the invention. For instance, manually operable or automatic means might be provided for permitting the railway vehicle to proceed with either end leading; the track circuit might be arranged for a single track operation or many other changes, additions or modifications might be made.

hat it is desired to secure by Letters Patent is .l. In an automatic stop system of the cont-inumisinductive type, the combination with car-carried apparatus acting to bring the train to a stop upon cessation of a controlling influence from the trackway, of means tor communicating such controlling influence to said car-carried apparatus continuously during the travel of the vehicle under clear trailic conditions and thereby maintaining said apparatus inactive, and for discontinuing the communication of such influences for a relatively short distance of travel at predetermined control points under dangerous trafiic conditions ahead and manually operable means, operable only after the vehicle has been brought to a stop, for releasing said apparatus.

2. In an automatic stop system, car-carried apparatus acting to bring the train to a stop on the cessation of a controlling influence received from the trackway, comprising a control relay having a stick circuit and a pick-up circuit; a second relay energized by said controlling influence for controlling said stick circuit; a manually operable circuit controller, located in a position accessible only When the train is at a stop, for controlling said pick-up circuit, and trackWay means for continuously transmitting said controlling influences under favorable traflic conditions and for cutting off said influences for a short distance of vehicle travel under unfavorable traiflc condit-ions.

3. In an automatic stop system of the continuous inductive type, the combination with car-carried apparatus acting to bring the train to a stop upon the cessation of a controlling influence, of means for continuously supplying said controlling influence from the trackway under favorable traflic conditions comprising track rails divided into insulated blocks, said blocks being normally energized throughout their length, means for shifting the point of application of energy to the track rails to a point a short distance from the exit ends of said blocks under unfavorable traflic conditions, whereby the train is brought to a stop near the end of each block under unfavorable trafficconditions, and manually operable means carried on the vehicle and accessible only from the ground for releasing the train from said. stop.

4. In an automatic stop system of the continuous inductive type, the combination With car-carried apparatus acting to apply the vehicle brakes and bring the train to a stop upon the cessation of a controlling influence, of means for communicating such controlling influence to said car-carried apparatus from the trackWay under favorable traflic conditions comprising track rails divided into insulated blocks, said blocks being provided with track relays, line relays operated from said track relays and controlling circuits for supplying currents to the entire length of said blocks under. clear traflic conditions and for supplying currents to all but a small portion at the ends of said blocks under unfavorable tratflc conditions ahead, and a vehicle carried manually operable device, accessible only after the vehicle has been brought to a stop, for releasing said brake application.

In testimony whereof I affix my signature.

WINTHROP K. HOWE. 

